Method of manufacturing of a formed product and use of the method

ABSTRACT

The invention relates to a method of manufacturing a product ( 10 ) formed in a pressing tool, wherein the tool is also designed to carry out a cutting and/or punching operation on the product. The cutting operation/punching operation is incomplete, such that waste/scrap ( 33, 41; 52; 64 ) resulting from the cutting/punching operation remains with the product ( 10 ) when the product leaves the pressing tool. The waste/scrap ( 33, 41; 52; 64 ) is removed during a subsequent finishing. The waste/scrap ( 33, 41; 52; 64 ) remains with the product ( 10 ) via at least one connecting bridge ( 31, 42; 51; 61 ) or the like.

TECHNICAL FIELD

This invention relates to a method of manufacturing a product formed ina pressing tool according to the pre-characterising part of claim 1. Theinvention also relates to the use of the method according to theinvention.

BACKGROUND OF THE INVENTION

E.g. in what are referred to as press-hardened sheet-metal products,subsequent cutting or subsequent punching is sometimes necessary inorder to meet prescribed contour requirements and/or in order to achievedesired hole configurations, etc., sometimes in combination with hightolerance requirements. A significant problem encountered withcutting/punching in, e.g. a press-hardening tool is how to removecutting/punching waste from the tool in a reliable and efficient manner.

One problem encountered when punching/cutting operations of this kindare carried out in the pressing tool is therefore the removing of theresulting cutting/punching waste from the pressing tool before a newinitial blank is supplied to the pressing tool. This therefore has anadverse effect on the rate of production.

In order to solve the abovementioned problem, the cuttingoperations/punching operations are generally carried out in a separatemachining station arranged downstream of the pressing tool.

By virtue of this invention, the required edge cutting/edge punchingoperations, hole cutting/hole punching operations, etc. can be carriedout in the pressing tool without encountering the abovementionedproblems. According to the invention, the cutting/punching waste is/aretaken along with the formed sheet-metal product when it is removed fromthe pressing tool for further transport in a processing line where thecutting/punching waste can be removed in a simple manner from the formedsheet-metal product without the risk of lost tolerance, etc.

In press hardening where a pre-heated sheet-metal blank is form-pressedin the pressing tool and then cooled in the pressing tool, subsequentpunching/cutting is particularly problematical on account of, interalia, increased tool wear as a result of the hardening. This inventionis particularly advantageous in this connection.

AIM OF THE INVENTION

One aim of this invention is to provide a method that minimizes the needfor subsequent working of, e.g. press-hardened products after they leavethe pressing tool.

Another aim is to achieve an increase in quality and efficiency comparedto the prior art.

The aim of the invention is achieved in that the method and the use havethe features specified in the claims.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 a is a perspective view of a press-hardened sheet-metal productin the form of what is referred to as a B-pillar for a passenger carafter forming, hardening and cutting/punching according to theinvention.

FIGS. 1 b-1 d are partial enlarged views illustrating cutting/punchingbridges according to the invention.

FIG. 2 is a diagrammatic cross section showing a first method ofweakening a bridge according to the invention.

FIG. 3 is a diagrammatic cross section showing another method ofweakening a bridge according to the invention.

DETAILED DESCRIPTION OF THE ILLUSTRATED EMBODIMENT

FIG. 1 a shows what is referred to as a B-pillar 10 for a passenger car,the said pillar/product/component being formed by press hardening.

The product 10 is manufactured from a flat sheet-metal blank which isheated, then formed in a forming tool and cooled while being held in thepressing tool/forming tool so as to obtain the desired hardness. Theaforementioned method of manufacture is referred to as press hardeningand results in dimensionally accurate sheet-metal products of highstrength since the sheet-metal component is pressed during the hardeningprocess.

The product 10 shown has a central part in the form of a hat-shapedsection with a central flange 15, two web parts 16, 17 and side flanges18, 19. The product 10 is provided at its upper and lower ends withparts 25, 26 for connection to a vehicle chassis.

The press-hardening tool (not shown) comprises an upper and a lower toolhalf shape-cooperating to give the desired final product configuration.

In connection with the forming operation carried out, it is necessary tocut/punch the outer contour of the product or portions of the said outercontour, as well as to cut/punch holes or hole patterns in the relevantproduct. In order to achieve combined forming, and possibly hardeningand cutting/punching, the forming tool is designed as a combination toolwith the desired properties.

The sheet-metal waste or sheet-metal scrap produced during thecutting/punching operation causes problems in that, inter alia, it isdifficult to remove the waste/scrap from the tool at the same rate atwhich the product is removed.

According to this invention, connecting bridges or land parts areproduced between the waste/scrap and the product so that the waste/scrapis taken along with the product as it is removed from the tool. Thewaste/scrap can thus be removed from the product in a simple manner in asubsequent step.

FIGS. 1 a and 1 b show a cut/punched hole 30, wherein, according to theinvention, a relatively narrow bridge/land 31 is left behind around thecircumference of the punched/cut cut 32. The centre part 33 of the hole,now in the form of scrap, thus remains with the product 10 via thebridge/land 31.

FIGS. 1 a, 1 c and 1 d show a punched/cut cut 40 for removing an outercontour part 41 for trimming the product 10. The outer contour part 41remains with the product 10 via at least one bridge/land 42. The outercontour part 41, now in the form of scrap, thus remains with the product10 via the bridges 42.

The presence of the abovementioned lands thus ensures that thewaste/scrap is taken along with the product 10 when it is removed fromthe tool. The width of the land may of course be selected so as toobtain the desired retention properties.

According to the invention, the land can also be weakened as desired inorder to further facilitate the removal of scrap.

FIG. 2 shows an example of weakening of the land 50 of this kind inwhich a transition region (bridge) 51 according to the invention isweakened by partial shearing, e.g. by cutting or punching in such amanner that a part 52 of the scrap can be removed, e.g. broken off, fromthe relevant product 10 when the product has left the tool. The figureshows two tool components 101, 102 effecting the said weakening of theland 50 in the form of a breaking notch or fracture notch.

FIG. 3 shows an example of alternative weakening of the land 60 in whicha transition region (bridge) 61 according to the invention is weakenedby a V-shaped indentation 62 resulting in a narrow part facilitating thesubsequent removal of a scrap part 64 from the product 10. The figureshows a tool component 200 with a V-shaped edge 201 which weakens theland 60.

It will be clear from the above that the lands/bridges according to theinvention can, if necessary, be weakened in many different ways otherthan those shown in order to facilitate the subsequent removal of scrap.

It should furthermore be noted that the invention is suitable for bothhot forming and cold forming. Press hardening is an example of anapplication for which the invention is particularly advantageous. Bothhot punching/hot cutting and cold punching/cold cutting may beappropriate in connection with the invention.

The invention may of course also be applied to the subsequent separationof what are referred to as multi-component couplings, i.e. when two ormore products are manufactured simultaneously in one tool.

In summary, it can be stated that the invention eliminates or simplifiessubsequent finishing, such as contour cutting and the making of holes inassociation with press hardening by providing complete cutting/completepunching in association with the press-hardening process, whereinlands/bridges are left behind, as a result of which waste/scrap is takenalong with a press-hardened product when it leaves the press-hardeningtool. The subsequent removal of waste/scrap from the product can befurther simplified by providing the lands/bridges with weakened areas inthe form of fracture notches or breaking notches. This allows for bothmanual and mechanised removal of scrap. The waste/scrap can thus beremoved from the product in a simple manner in a subsequent operationby, e.g. cutting, punching or shearing or by breaking the lands/bridges.

It will thus be clear that the invention can be applied tocomponents/products of any desired configuration. The invention is thusnot limited to what is illustrated and described here, and amendmentsand modifications are possible within the scope of the following claims.

1. Method of manufacturing a product (10) formed in a pressing tool,wherein the tool is also designed to carry out a cutting and/or punchingoperation on the product, characterised in that the cuttingoperation/punching operation is incomplete, such that waste/scrap (33,41; 52; 64) resulting from the cutting/punching operation remains withthe product (10) when the product leaves the pressing tool.
 2. Methodaccording to claim 1, characterised in that the waste/scrap (33, 41; 52;64) is removed during a subsequent finishing.
 3. Method according toclaim 1, characterised in that the waste/scrap (33, 41; 52; 64) remainswith the product (10) via at least one connecting bridge (31, 42; 51;61) or the like.
 4. Method according to claim 3, characterised in thatthe connecting bridge (51; 61) is of reduced thickness in relation tothe thickness of the material of the product (10) at a cuttingpoint/punching point.
 5. Method according to claim 3, characterised inthat the cutting operation/punching operation is carried out in such amanner that the connecting bridge (51) is partly sheared off.
 6. Methodaccording to claim 3, characterised in that the cuttingoperation/punching operation is carried out in such a manner that theconnecting bridge (61) is compressed.
 7. Use of a method according toclaim 1, characterised in that the method is used in association withmanufacture of press-hardened products so as to minimize or eliminatesubsequent finishing of a hardened product.
 8. Use of a method accordingto claim 1, characterised in that the method is used in hot-forming ofproducts, wherein the cutting operation/punching operation is carriedout on a heated product.
 9. Use of a method according to claim 1,characterised in that the method is used in cold-forming of products.10. Use of a method according to claim 3, characterised in that themethod is used in a simultaneous manufacture of at least two products,and in that the products remain together via at least one connectingbridge or the like.
 11. Method according to claim 2, characterised inthat the waste/scrap (33, 41; 52; 64) remains with the product (10) viaat least one connecting bridge (31, 42; 51; 61) or the like.
 12. Methodaccording to claim 4, characterised in that the cuttingoperation/punching operation is carried out in such a manner that theconnecting bridge (51) is partly sheared off.
 13. Method according toclaim 4, characterised in that the cutting operation/punching operationis carried out in such a manner that the connecting bridge (61) iscompressed.
 14. Method according to claim 11, characterised in that theconnecting bridge (51; 61) is of reduced thickness in relation to thethickness of the material of the product (10) at a cuttingpoint/punching point.
 15. Method according to claim 14, characterised inthat the cutting operation/punching operation is carried out in such amanner that the connecting bridge (51) is partly sheared off.
 16. Methodaccording to claim 14, characterised in that the cuttingoperation/punching operation is carried out in such a manner that theconnecting bridge (61) is compressed.
 17. Use of a method according toclaim 2, characterised in that the method is used in association withmanufacture of press-hardened products so as to minimize or eliminatesubsequent finishing of a hardened product.
 18. Use of a methodaccording to claim 2, characterised in that the method is used inhot-forming of products, wherein the cutting operation/punchingoperation is carried out on a heated product.
 19. Use of a methodaccording to claim 2, characterised in that the method is used incold-forming of products.
 20. Use of a method according to claim 4,characterised in that the method is used in a simultaneous manufactureof at least two products, and in that the products remain together viaat least one connecting bridge or the like.